This invention relates to a robotic apparatus for the assembly of automobiles and to an assembly method employing this apparatus. More particularly but not exclusively, it relates to a robotic apparatus and method for mounting wheels on automobile bodies.
Industrial robots have come to be extensively used in the manufacture of automobiles. Early industrial robots employed complicated electromechanical devices for controlling the motions of the robot. More modern robots employ a video camera to form an image of the positions and orientations of objects to be manipulated by the robot, and the movements of the robot are controlled in accordance with the video image.
Typically, the video camera is mounted atop the robot and is aimed at the object which is to be manipulated by the robot. A computer processes the video image formed by the camera, performs recognition of the objects in the processed image, and then controls the movement of the robot so as to manipulate the object. Frequently, a robot must move between several work stations and transfer objects between the stations. For example, a robot for mounting wheels on automobile bodies must move between a wheel conveyor, where the robot grasps a wheel, and a vehicle body, where the robot mounts the wheel on a brake drum of the vehicle. At each station, optical recognition must be performed before the robot can pick up or mount a wheel. Since the video camera is mounted atop the robot, the optical recognition can begin only after the robot has pivoted to a station where it is to perform a task. The robot must then sit idle at this station until image processing, which may take a substantial length of time, is completed. Thus, in the operation of a conventional robotic assembly apparatus, there is much wasted time in which the robot is not performing any task but is simply waiting for image processing to be performed.